With the ever increasing reliance on electrical power in homes and industry, power outages caused by breakdowns in electrical utility equipment become, at the very least, extremely aggravating. It is for this reason, plus the frequency of disruptions in utility electrical service, that standby generating equipment to supply at least critical load circuits has become popular. To accommodate these alternative electrical sources supplying common electrical load circuits, a so-called power transfer switch is utilized. This transfer switch normally is conditioned to connect the utility source to the common load circuits, while maintaining the standby generating equipment disconnected therefrom. Upon the occurrence of a power outage, the transfer switch is reconditioned either automatically or manually to first disconnect the utility source and then connect the standby source to the common load circuits. Obviously, precaution must be taken to insure that the two sources can never be simultaneously connected to the common load circuits.
Transfer switches serving this end have typically been quite expensive, complicated in design, and difficult to operate. It is therefore a principal object of the present invention to provide an improved transfer switch which is simple in design, convenient and reliable in operation, and inexpensive to manufacture.